identified by their unique dog tags. cnn couldn't independently corroborate the account. >> we need to find all these people, and they need to go to the court. they absolutely illegal. >> reporter: wagner contractors surfaced in 2014, exposed by research groups and cnn investigations. their operations span the middle east and africa. u.s. officials accuse wagner of multiple human rights abuses in multiple countries. in this disturbing 2017 video, investigated by cnn, wagner mercenaries appear to be torturing and murdering a syrian man, as they make jokes. the kremlin said the incident had nothing to do with the russian military operations in syria, and they've repeatedly denied any links to wagner. u.s. officials say that wagner was started by this man, dmitry utkin, a veteran of the chech